Malaria is a leading cause of mortality in children across the tropics. Additionally, the debilitating effects of malaria result in lost work productivity and consume considerable public healthcare resources in those regions. As a result, malaria is an element in a cycle of poverty and disease that can be effectively controlled through medicine, bed nets, and rudimentary mosquito control. Unfortunately, efforts to control malaria have been thwarted in many areas by the widespread proliferation of counterfeit and poor quality antimalarial drugs.
Poor quality drugs or counterfeits pose an immediate threat to public health and undermine malaria control efforts and contribute to observed treatment failures as well as expose malaria parasites to low drug levels, resulting in early loss of the usefulness of effective life-saving drugs, i.e. the artemisinins. There has been documented evidence of death as a result of patient unwittingly taking fake artesunate (Newton P N, McGready R, Fernandez F, Green M D, et al. (2006). Manslaughter by Fake Artesunate in Asia-Will Africa Be Next? PLoS Medicine 3: 1-4). The urgency of the problem was further highlighted by the report of an international multi-disciplinary effort that recently led to a major bust of some of the counterfeit artesunate manufacturers (Newton P N, Fernandez F M, Plancon A, Mildenhall D C, Green M D, Ziyong Li, Christophel E M, Phanouvong S, Howells S, McIntosh E, Laurin P, Blum N, Hampton C Y, Faure K, Nyadong L, Soong C W R, Santoso B, Zhiguang W, Newton J, Palmer K (2008). A Collaborative Epidemiological Investigation into the Criminal Fake Artesunate Trade in South East Asia. PLoS Medicine 5 (e32):209-19.
A study detailed in the World Health Organization Fact Sheet 94 estimates that between 25 and 50 percent of medicines consumed in the developing world are counterfeit. A specific survey of antimalarial drugs conducted in Nigeria found 48 percent of all tested drugs were found to be of poor quality and 88 percent of the tested chloroquine phosphate tablets were of poor quality (Newton P N, McGready R, Fernandez F, Green M D, et al. (2006). Manslaughter by Fake Artesunate in Asia-Will Africa Be Next? PLoS Medicine 3: 1-4). A study reported in 2007 found that 29 percent of the tested artemisinin-derived antimalarials collected in Kenya and the Democratic Republic of Congo were under dosed and the samples with the lowest effective drug content were artemisinin injectables. Artemnkeng M A, DeCock K, Plaizier—Vercammen J (2007). Quality Control of Active Ingredients in Artemisinior—derived Antimalarials within Kenya and OR Congo. Tropical Medicine and International Health 1211-68-74.
The profiteering associated with the production of counterfeit and poor quality antimalarial drugs is expected to hamper World Health Organization efforts to use artemisinin combination therapy (ACT) in areas experiencing malaria. Owing to the high cost of artemisinin, the high demand created for the therapeutic created by World Health Organization promotion of this family of therapeutics, and poorly controlled drug chain of custody all create a favorable situation for the counterfeiting and producing of artemisinin compounds in dosages.
While the testing of artemisinin compounds in a dosage is a straightforward and routine process in a conventional analytical lab, field testing of antimalarials is often precluded by a lack of such facilities as a chromatograph, let alone a separation column coupled to a spectrometer such as infrared, mass, ultraviolet-visible, or nuclear magnetic resonance. Additionally, conventional analytical laboratory instrumentation is often functionally incompatible with the operating environment of a field health worker.
Green et al. have described colorimetric reactions of artemisinins, i.e. artesunate, dihydroartemisinin, and artemether using diazonium salts (Green M D, Mount D L, Wirtz R A (2001). Authentication of artemether, artesunate and dihydroartemisinin antimalarial tablets using a simple colorimetric method. Trop Med Int Health 6(12):980-2; Green M D, Mount D L, Wirtz R A, White N J. (2000). A colorimetric field method to assess the authenticity of drugs sold as the antimalarial artesunate. J Pharm Biomed Anal. 24(1):65-70). These reactions require the conversion of the artemisinin compound to unsaturated decalone or enolate/carboxylate followed by the reaction with the diazo dye to produce a yellow color. For artesunate and dihydroartemisinin, the conversion to the enolate/carboxylate was achieved by using a strong base, while artemether was converted to the decalone use a strong acid. The pH of the solutions were adjusted to 4 (artesunate and dihydroartemisinin) or 8 (artemether) in order for the reaction with the diazonium salt to occur. These methods required the use of a higher buffered solutions and a second derivatization step for the color to develop.
Thus, there exists a need for a safe, one step process for testing a composition for an antimalarial dosage present in a therapeutically effective amount of an artemisinin derivative that is inexpensive and colorimetric. Additionally, there exists for a kit embodying such a process that is operated by an individual with no laboratory training, equipment, or safety gear.